1. Field of the Invention
The present general inventive concept relates to an image forming apparatus to form an image onto a printing medium.
2. Description of the Related Art
Generally, a convergence type image forming apparatus such as a multi-function unit incorporating functions of a printer, a copier or a facsimile, has a main function of printing an image onto a printing medium. The image forming apparatus includes a feeding unit to feed a printing medium, an image forming unit to form an image, a transfer unit to transfer the image onto printing medium, a fixing unit to fix the image into the printing medium, and a discharge unit to discharge the printing medium to an outside thereof after the printing. FIG. 1 illustrates examples of a fixing unit 40 and a discharge unit 50 of a conventional image forming apparatus.
Referring to FIG. 1, the fixing unit 40 of the conventional image forming apparatus includes a heating roller 41 and a pressing roller 42 rotated in tight contact with each other. The discharge unit 50 includes a discharge roller 51 provided at an exit side of a printing medium passing between the heating and pressing rollers 41 and 42, and an idle roller 53 to rotate in tight contact with the discharge roller 51.
The heating and pressing rollers 41, 42 are rotatably supported on a frame 43, and the discharge roller 51 is disposed on a discharge guide 52 which is pivotable about the frame 43. The idle roller 53 is mounted on the frame 43 at a position facing the discharge roller 51. A plurality of rotatable guide protrusions 54 are formed on the frame 43, in proximity to the heating roller 41, to guide the printing medium being discharged. The rotatable guide protrusions 54 are elastically supported by elastic springs (not shown), so that when rotated, the rotatable guide protrusions 54 are elastically biased towards the original position.
An unsuccessful conveyance of the printing medium, such as jamming, occurs during an image fixing process. In this case, a user controls the discharge guide 52 to pivot and move away from the frame 43 to expose the heating and pressing rollers 41 and 42 to an outside thereof, so as to remove the jammed printing medium.
The jammed printing paper is caught at the guide protrusions 54 nearby the heating roller 41, and torn apart. The elastic springs supporting the guide protrusions 54 are deformed or displaced from an original position, by an excessive force exerted by the user to remove the printing medium.
Meanwhile, the fixing unit 40 generates heat of approximately 200° C. in the fixing process. As the heat is transmitted to an upper cover (not illustrated) that forms the outer side of the fixing unit 40, to cause damages, such as changed color, or deformation. In addition, user access is limited when the upper cover is heated.
The heat from the fixing unit 40 is also radiated to the neighboring components stacked at an upper portion of the image forming apparatus such as scanning unit, to cause malfunction or operation failure of the affected components.